1. Field of the Invention
The invention relates generally to applicators and dispensers for releasing predetermined quantities of liquid or vaporizable material. More particularly, the invention relates to flexible liquid containing packages comprising multiple compartments for maintaining at least one liquid composition isolated from the ambient until use.
2. Description of the Prior Art
Flexible packages for containing a variety of solid or liquid substances are commonly used in order to enable a user to conveniently handle the contained product until immediately prior to use at which time the package may be relatively easily opened. As used herein, the term "flexible" means a generally flat package or pouch formed from a pair of thin, pliable sheet members sealed together to form an interior space. Often the contents of the flexible package include at least one additional internal container (within the interior space) filled with a material which must be maintained separate from the remaining contents of the package until immediately prior to use.
For example, U.S. Pat. No. 2,864,492 (Lappala) shows a flexible package having an outer container containing a polymerizable material as well as a separate, inner rupturable container (pocket or capsule) containing a catalyst. The outer container is made of material impervious to liquids and impervious to the particular polymerizable material contained within. When the inner container is ruptured and the contents of the inner and outer containers are mixed, the outer container may be cut to release the mixed contents. Another example of a multiple compartment flexible package is shown in U.S. Pat. No. 3,343,664 (Poitras) which discloses a dispenser of a vaporizable liquid composition, the dispenser having a rupturable, liquid impermeable inner pouch within a permeable outer pouch, the inner pouch adapted to be torn without tearing the outer pouch.
Flat, multicompartment, flexible packages have been adapted for dispensers of air-treating products as disclosed in U.S. Pat. Nos. 4,558,820 (Harris Jr.) and 4,502,360 (Haworth et al). Each of these patents shows an air-treating, vapor dispensing device in the form of a flat permeable dispensing pouch supported between a pair of rigid, apertured support members, the pouch including an impermeable inner storage container filled with a flowable, vaporizable air-treating composition. The dispenser is activated when the inner container is ruptured by forcing the two opposing support members together to thereby release the composition into the flexible permeable dispensing pouch. The composition diffuses through the surfaces of the pouch and is released at the outer surfaces of the pouch as a vapor.
One disadvantage of all known flexible packages having sealed outer containers and rupturable inner containers is that they may rupture at the outer seal if the inner seal breaks at a point which directs the bursting force directly at the outer sealed edge. This is especially true if the outer edge is heat sealed. U.S. Pat. No. 4,660,763 (Gutkowski et al.) recognizes this disadvantage and discloses an air freshener having a reservoir for receiving the liquid in the pouch should the outer seal break upon activation. Nevertheless, in some instances leaks still occur.
Another disadvantage of prior art flexible pouches is that when they are supported vertically (as in Harris, Jr.) the liquid contents tend to pool in the bottom of the outer pouch, thus decreasing operational efficiency, unless the opposing surfaces of the package are kept very close together by an auxiliary support frame to keep the liquid spread out by adhesive attraction between the liquid and the surfaces. Harris, Jr. also provides an auxiliary support frame having a pair of opposed vertical planar supports which keep the pouch flat thereby relatively evenly distributing the liquid throughout the pouch.
It is an object of this invention to provide a dispenser of air-treating compositions in the form of a flat, flexible package which avoids pooling and achieves even distribution of liquid over a large portion of a flexible package without the necessity for auxiliary rigid support structures.
Some flexible packages such as those shown in U.S. Pat. Nos. 3,608,709 (Pike) and 4,534,509 (Holzner) use multiple compartments separated by an internal seal intended to rupture to enable communication between the compartments. The Holzner patent discloses a multiple compartment plastic package where the compartments are separated by a rupturable seal formed by the opposing sides of the plastic package being sealed along a rupturable, polymer plastic foam material. Holzner is directed in part to a mechanism to control rupture strength by inserting the polymeric material between the package sides which are sealed together. The manufacturing complexity of this structure is an obvious disadvantage.
The possibility of rupturing the outer package seal has received considerable attention in the prior art and numerous sealing techniques are known in addition to Holzner. Prior art dispensers have generally attempted to solve the bursting force problem by either providing excessive volume in the outer pouch (as shown, for example, in the Hayworth, Harris, Jr., and Gutkowski patents) or by providing separate compartments separated by a breakable seal (as shown in Pike and Holzner). In addition to integrity of the seal itself, volumetric capacity of multi-compartment flexible packages must be considered. Excessive volume in the outer pouch would cause it to act as a reservoir and allow liquid to pool. Too little volume in the outer pouch may, in addition to risking breaking the outer seal, prevent the liquid bursting from the inner pouch from flowing around the "squeeze point".
It is another object of this invention to provide a multiple compartment, flexible package having a rupture force control mechanism for reducing the force directed against the outer seal upon rupture of an inner, liquid bearing container. As will be shown below, the present invention effects rupture force control through an impregnatable member which acts somewhat as a shock absorber and provides additional advantages.
An additional advantage provided by the present invention is the combination of the composition-segregating characteristics of multiple compartment packages with liquid applicators. Thus, liquid-impregnated cleaning absorbent members or wipes may be maintained dry prior to use. It is known to provide packages, in both air diffusion and liquid applicator embodiments, having already impregnated absorbent member sealed by impenetrable barrier films. For example, U.S. Pat. No. 4,277,024 (Spector) discloses an aroma-dispensing tab in a package which is stickable onto a surface. The tab comprises an impregnated base with a perforated dome and is hermetically sealed in a foil package which must be torn open to remove the tab. U.S. Pat. No. 4,762,124 (Kerch et al.) and U.S. Pat. No. 4,372,098 (Mason) each disclose an impregnated, absorbent applicator for dispensing liquid. In Kerch the applicator is supported on a support layer and covered by a permeable dispensing membrane which is in turn covered by an impervious cover which must be peeled away prior to use. All the various layers are sealed together along a common boundary. The Mason structure is similar but without the intermediate permeable membrane. U.S. Pat. No. 4,145,001 (Weyenberg et al.) and U.S. Pat. No. 4,161,283 (Hyman) disclose a similar structure for dispensing volatile substances through a permeable membrane (rather than liquid per se). The devices of these patents necessarily use a relatively large amount of barrier film because the already impregnated absorbent member must be completely covered. The volume and surface area of the absorbent member must necessarily be greater than that of any container of the active material alone. Consequently, the amount of barrier material required is significantly greater than if the active liquid had been maintained in a separate compartment (as in the air diffusion devices) which could be subsequently ruptured immediately prior to use.
It is another object of this invention to provide a liquid applicator or dispenser in which the liquid is maintained separate from an impregnatable or absorbment member until just prior to use, thereby decreasing the amount of liquid-impervious barrier material required to preserve the liquid.
Very often the difference between vapor dispensing packages and liquid applicator packages is one of degree. For example, in those prior art embodiments of flexible packages containing absorbent material, the absorbent material is permitted to retain only a relatively small amount of active vaporizable material so that an accumulation of liquid is prevented since the object of the device in these cases is to dispense vapor, not liquid. In those embodiments where the device is intended to be used as a liquid applicator, the absorbent material is provided with a sufficient amount of liquid to enable the liquid to be dispensed. In both instances, the package must be sealed prior to use. In any event, prior art liquid applicators are generally not adaptable for use as air diffusers and vice versa. It would improve manufacturing efficiencies to produce a flexible package capable of easily being adapted to either use. It would further be desirable to provide a liquid applicator package incorporating some of the technology associated with air treating dispensers (such as keeping active components separated until immediately prior to use). Having a package adaptable to either use would be a benefit because a common, base package easily adaptable for one use or the other with a minimal number of manufacturing changes.
It is a further object of this invention to provide a dispenser suitable, with only minor changes, for either the application of liquids to a desired surface or the dispensing of vaporizable air-treating compositions.
No one prior art multiple compartment flexible package is able to efficiently mix a plurality of separated compositions without repeatedly transfering them between the original compartments (as in Holzner) or kneading the package (as in Lappala and Poitras). It is, therefore, a further object of this invention to provide a multiple compartment flexible package capable of efficiently mixing liquid components without additional manipulation.
It is yet another object of this invention to provide a multiple compartment flexible package enabling the impregnation of an absorbent dispensing member prior to use rather than at the time of manufacturing.